1. Field of the Invention
The present invention relates to generally to an electronically controlled sample warper having one or a plurality of yarn introduction means for winding yarns on a warper drum to automatically exchange yarns and wind the yarns on a warper drum in accordance with a preset yarn order, and more particularly to an electronically controlled sample warper which enables efficient exchanging of yarns to be wound, a high speed warping method using the warper, and a yarn draw-back device capable of rapidly solving yarn looseness.
2. Description of the Related Art
As a conventionally used electronically controlled sample warper, there is known a structure disclosed, for example, in Japanese Patent Publication No. 8736/1989, as illustrated in FIGS. 14-18. This known electronically controlled sample warper W has a hollow shaft 1 (FIG. 14). Driving and driven shafts 2, 3 project centrally from opposite ends of the hollow shaft 1. A small gear 5 fixed to a pulley 4 and a pulley 99 are loosely mounted on the driving shaft 2, while a small gear 7, to which a warn introduction means 6 is fixed, is loosely mounted on the driven shaft 3 at the distal end. While the illustrated example shows only one yarn introduction means 6, two or more yarn introduction means 6 must be disposed for a plural-winding system.
The small gears 5, 7 are associated with each other through small gears 9, 10 disposed at opposite ends of an associating shaft 8 extending through the hollow shaft 1, which small gears 9, 10 are meshed with the corresponding small gears 5, 7. The hollow shaft 1 is cantilevered at the driving shaft 2, and a warper drum A is loosely mounted on the hollow shaft 1 on the driven shaft 3 side.
As illustrated in FIG. 15, the warper drum A is formed of drum frames 13, 14 having an outer periphery of like shape having alternately an arcuate portion 11 and a straight portion 12; a pair of rollers 15 disposed one on the arcuate portion 11 of each of the drum frames 13, 14; and horizontal beams 16 carrying the rollers 15 around which conveyor belts 17 (FIG. 14) are wound. The conveyor belts 17 are moved along a plane formed by the horizontal beams 16.
The conveyer belts 17 are simultaneously driven to a common amount of fine movement by a drive member 21 threadedly engaged with interior screw shafts 20 of planetary gears 19 concurrently rotated by meshing with a sun gear 18 suitably driven from the exterior. The distal end of the yarn introduction means 6 is bent inwardly to provide a yarn introducing member 6' which is disposed adjacent to the front end of the outer periphery of the warper drum A. It goes without saying that the movement of the conveyor belts 17 may be carried out by any known driving means other than the above-mentioned structure.
Referring again to FIG. 14, B designates a fixed creel for supporting a plurality of bobbins around which different kinds (different color or different twisting) of yarns 22 are wound; 24, a guide plate for guiding yarns 22 drawn out from the bobbins; 25, a tension regulator for regulating the tension of the yarns 22; 26, a dropper ring; 30, a guide rod for the yarns 22; and E, a yarn fastener having a permanent magnet mounted to a base Y for pressing and setting the yarns.
Further in FIG. 14, reference numeral 27 designates a yarn selection guide unit having a plurality of yarn selection guides 27a-27j (FIG. 18) for selecting and guiding the yarns 22 according to instructions from a program setting unit 78 (FIG. 17). Reference numeral 28 designates a slitted plate which generates pulses in response to the rotation of the pulley 4 to actuate a plurality of rotary solenoids 29 arranged corresponding to the yarn selection guides 27a-27j. The yarn selection guides 27a-27j are mounted to their respective associated rotary solenoids 29 such that they are pivotally moved to advance to an operative position (yarn exchange position) when the rotary solenoids 29 are turned on, and they are pivotally moved in the opposite direction to restore to a standby position (yarn accommodating position) when the rotary solenoids 29 are turned off.
Referring next to FIG. 16, reference numerals 33, 34 and 38 designate shedding bars for jointly forming a shed of the yarns 22, where the bars 33, 38 are upper shedding bars, and the remaining bar 34 is a lower shedding bar. 35 and 37 designate cut shedding bars for separating the shedding down yarns into lower-side yarns and upper-side yarns, where one of the bars 35 is a cut shedding up bar, and the other bar 37 is cut shedding down bar. It should be noted that in FIG. 17, the illustration of the upper shedding bar 38 is omitted.
Reference numeral 39 designates a yarn stopper mounted on the dram frame 13 for stopping a yarn immediately under the broken yarn being shedded (FIG. 15). A rewinder C is composed of a skeleton 40, a pair of rollers 41, 42, a zigzag-shaped comb 43, a roller 44 and a beam 45 for a woven fabric (FIGS. 15 and 16).
Referring again to FIG. 14, reference numeral 46 designates a main motor implemented by an invertor motor for enabling, during operation of the warper, acceleration and deceleration, buffer start/stop, jogging operation and an increased winding speed.
Further in FIG. 14, reference numeral 47 designates a main speed change pulley; 58, a V belt wound on and between the main speed change pulley 47 and an auxiliary speed change pulley 48; 49, a counter pulley which is coaxial with the auxiliary speed change pulley 48; and 50, a brake actuating pinion for reciprocatingly moving a rack to bring the rack into and out of engagement with a brake hole (not shown) in a brake drum D, thus controlling the warper drum A as desired. Reference numeral 57 designates a belt between pulleys 4 on the driving shaft 2; 51, a belt moving motor (AC servo motor); 52, a shift lever; 54 a sprocket-wheel; 55, a chain; 56, a chain wheel for driving the sun gear 18; 57, 58, both V belts; 59, a front cover; 59a, a front guide rod; and D, the brake drum.
Reference numerals 67a, 67b designate sensors for detecting the passing of the slit of the slitted plate 28.
The slitted plate 28 is set to rotate synchronously with the yarn introduction means 6, so that the rotation of the yarn introduction means 6 is also sensed by the sensors 67a, 67b by detecting the rotation of the slit of the slitted plate 28. These sensors 67a, 67b actually comprises three sensors which are arranged at an angular space of about 120 (only two of them are illustrated in the figure).
Referring next to FIG. 17, reference numeral 69 designates a movement/stopping change-over lever for the conveyor belts 17; 70, a locking lever for locking the warper drum A; 74, a shedding bar adjusting lever; 75, a shedding bar locking handle; 78, a program setting unit; 79, a controller; 80, a yarn tensioning unit located centrally on the straight part 12 of the warper drum A; and S, a stopper plate disposed on the base Y corresponding to the yarn selection guide unit 27.
The foregoing electronically controlled sample warper, which has been developed by the present applicant, is favorably accepted as being capable of automatic pattern warping through electronic control.
However, since the conventional electronically controlled sample warper as described above employs an ordinary general-purpose motor as a main motor, there are still several problems to solve. First, it is impossible to increase and/or decrease the rotating speed during operation. Miscatching and mischanging inevitably occur during exchange of yarns. Yarns are more susceptible to breakage. In addition, the conventional electronically controlled sample warper is not capable of performing buffer start/stop, jogging operation and so on, so that there have been room for improvement in terms of operation efficiency.
In addition, with respect to a warp density setting method and a mechanism employed thereby, a moving speed of a conveyor belts is determined by changing a gear ratio of a transmission connected to a main motor with a warp density setting dial, and the conveyor belts operate even during idling, so that yarns cannot be regularly wound on a warp drum, causing minute changes in tension and warp length during winding.
The present applicant has also developed and proposed electronically controlled sample warpers which employ an invertor motor and an AC servo motor in order to eliminate the inconveniences mentioned above (Japanese Patent Publication Nos. 64-10609 and 64-10610). The respective electronically controlled sample warper is provided with a fixed creel for supporting a plurality of bobbins around which different kinds of yarns (yarns of different colors or differently twisted yarns).
The present applicant has also developed and proposed an electronically controlled sample warper which is capable of simultaneously warping a plurality of yarns (Japanese Patent Publication No. 4-57776). This electronically controlled sample warper eliminates the need for a yarn exchange process to suppress time loss for yarn exchange to zero. In addition, since a plurality of yarns can be simultaneously wound on a warper drum, a warping operation time can also be reduced.
Since this electronically controlled sample warper capable of simultaneously warping a plurality of yarns is provided with a plurality of yarn introduction means, a conventional fixed creel cannot support it. For this reason, a rotary creel has been developed, together with the development of the electronically controlled sample warper capable of simultaneously warping a plurality of yarns, for simultaneously warping a plurality of yarns. The development of this rotary creel enables a plurality of yarns to be simultaneously warped, consequently realizing a reduction in a warping time.
The present applicant has also proposed an electronically controlled sample warper capable of aligned winding, wherein after a first column of yarns has been wound on a warper drum, the next column of yarns is wound such that the beginning of the yarns of the next column are positioned in front of the yarns of the first column, thereby making it possible to achieve aligned winding warping in order from the lower yarns on the warper drum, and to facilitate winding of yarns to a weaving beam even if a warping length is longer (Japanese Patent Laid-open Publication No. 7-133538).
Likewise, this improved version of the electronically controlled sample warper has been highly favorably accepted.
In the proposed electronically controlled sample warper mentioned above, a yarn exchanging operation is performed as follows.
A yarn 22 drawn out from a bobbin is threaded through a tension regulator 25 on a tension base, a double winding/mischange detecting sensor and a drop ring 26, and is passed on a yarn selection guide unit 27 of the electronically controlled sample warper W.
When a start-up switch is turned on, a yarn selection guide 27a-27j of the yarn selection guide unit 27 having a number indicated by previously inputted pattern data is operated to wind a yarn 22 around a warper drum A by the rotation of the yarn introduction means 6. After an indicated number of yarns have been warped, the yarn selection guides 27a-27h having the above-mentioned numbers and a yarn removing unit 32a are operated so that the yarns 22 are removed from the yarn introduction means 6 by the yarn removing unit 32 and are accommodated in the associated yarn selection guides 27a-27j.
Next, in the order of the pattern data, a yarn selection guide 27a-27j having the next indicated number is operated to supply the yarn introduction means 6 with a yarn 22 to wind the yarn 22 on the warper drum A. After an indicated number of yarns have been warped, the yarn selection guides 27a-27h having the above-mentioned numbers and a yarn removing unit 32a are operated so that the yarns 22 are removed from the yarn introduction means 6 by the yarn removing unit 32 and are accommodated in the associated yarn selection guides 27a-27j.
In this way, the yarn selection guides 27a-27j and the yarn removing unit 32a are operated in the order of the pattern data to execute yarn exchange to warp a stripe pattern on the warper drum A. The yarn exchanging mechanism will be described in a more specific manner with reference to FIGS. 18-25.
Referring first to FIG. 18, a yarn selection guide unit 27 has a plurality of yarn selection guides 27a-27j for selectively guiding yarns 22. A rotary solenoid 29 is attached to each of the yarn selection guides 27a-27j, such that the yarn selection guides 27a-27j are pivotally moved to advance to an operative position (yarn exchange position) when the rotary solenoids 29 are turned on, and they are pivotally moved in the opposite direction to restore to an original standby position when the rotary solenoids 28 are turned off. The conventional yarn exchanging mechanism uses the yarn introduction means 6 to sequentially exchange yarns and wind the yarns on the warper drum A. A yarn 22 supplied from a fixed creel B passes between a front cover 59 and a stopper plate S, and is held by the yarn introduction means 6 and wound on the warper drum A. As illustrated in FIG. 19 (a yarn selection guide 27e is illustrated), the conventional yarn selection guides 27a-27j are each formed of a straight arm having a distal end portion bent in the same direction as the rotating direction of the yarn introduction means 6.
Next, description will be made on how a yarn 22a of a yarn selection guide 27a, for example, is exchanged to a yarn 22e of the yarn selection guide 27e in the yarn exchanging mechanism in the conventional electronically controlled sample warper with reference to FIGS. 20-25. First, a yarn removing unit 32 mounted to the base Y is actuated, and the yarn 22a is removed from the yarn introduction means 6 by a yarn removing part 32a after the yarn introduction means 6 has passed over the yarn selection guide unit 27 (FIG. 20). The removed yarn 22a is guided between the base Y and a stopper plate S by a front guide rod 59a protrusively formed on the inner surface of a lower portion of the front cover 59, and pressed to the stopper plate S, so that the yarn 22a abuts to a yarn selection guide 27a which is advanced to the yarn exchange position (FIG. 21).
As the yarn selection guides 27a is pivotally moved toward the base Y and accommodated therein at the standby position, the removed yarn 22a is also held by the yarn selection guide 27a and accommodated together in the base Y (FIG. 22).
The yarn selection guide 27e of the yarn 22e to be next wound is pivotally moved from the base Y to the stopper plate S to reach the yarn exchange position (FIG. 23). Then, as the yarn introduction means 6 passes the position of the yarn selection guide 27e, the yarn 22e is held by the yarn introduction means 6 and wound on the warper drum A (FIG. 24). While the yarn 22e is being wound on the warper drum A, the yarn selection guide 27e is pivotally moved to the base Y and accommodated in the standby position (FIG. 25). The yarn exchange is carried out through the foregoing operations.
This conventional yarn exchange mechanism, however, requires the yarn removing part 32a interposed between the yarn introduction means 6 and the stopper plate S when the yarn 22 is removed from the yarn introduction means 6 to prevent the yarn extending from the fixed creel B to the yarn removing part 32a from moving in the rotating direction.
The yarn 22 prevented from moving in the rotating direction by the yarn removing part 32a slides on the yarn introduction means 6 and comes off the yarn introduction means 6.
In this event, the yarn 22 removed from the yarn introduction means 6 must be supplied from the fixed creel B until the yarn 22 abuts to the yarn removing part 32a and it is removed from the yarn introduction means 6. Also, a yarn path is different when the yarn is being wound around the warper drum A and when the yarn is exchanged, causing the length of yarn required for yarn exchange to be longer. In addition, since the yarn removing part 32a is used, certain impact is applied to the yarn when it is removed from the yarn introduction means 6.
In other words, when the yarn is accommodated during the yarn exchange, the action of the yarn removing part 32a prevents the yarn 22 caught by the yarn introduction means 6 from advancing. Further, since the yarn 22 is being removed from the yarn introduction means 6, the yarn is physically loosened.
Particularly, when a yarn is to be accommodated in a yarn selection guide far from the yarn removing part 32a, for example, in the yarn selection guide 27j, yarn looseness amounts to two times or more as compared with that when a yarn is accommodated in the yarn selection guide 27a. For removing the yarn looseness and guiding the yarn toward the yarn selection guides 27a-27j, a dropping force of a drop ring 26 plays an important role. Specifically, as the drop ring 26 is physically heavier, the yarn looseness can be removed faster.
However, as the drop ring 26 is heavier, a dropping distance of the drop ring 26 becomes longer, so that the weight of the tension regulator 25 on the fixed creel B must be increased for reducing the dropping distance of the drop ring 26.
As a result, the yarn is applied with a larger tension, so that yarn breakage is more likely to occur due to excessive tension to the yarn while the yarn is supplied to the yarn introduction means during the yarn exchange, or during warping.
However, when the weight of the drop ring 26 is reduced, and the weight of the tension regulator 25 on the fixed creel B is also reduced to apply a smaller tension to the yarn, a longer time is taken to remove yarn looseness when the yarn is accommodated during the yarn exchange, causing a failed yarn exchange and an increased number of times of a weaver being stopped, consequently leading to a reduced operating efficiency in any case.
For this reason, in the conventional electronically controlled sample warper, the rotational speed of the yarn introduction means or warping speed (yarn speed) is reduced during yarn exchange from a warping speed (yarn speed) assumed when yarns are not exchanged (for example, 800 meters/minute for yarn speed during warping, and 250 meters/minute for yarn speed during yarn exchange), so as to reduce the number of times a weaver must be stopped due to failed yarn exchange, even if a light drop ring 26 is employed.
However, a reduced warping speed during yarn exchange causes a problem in that a warping time becomes correspondingly longer, particularly an excessively long time is required when warping is performed for a cross-striped pattern which involves frequent yarn exchanges. In addition, there is no existent apparatus which can rapidly and efficiently remove or eliminate yarn looseness.
The present inventors have repeatedly investigated an apparatus which could solve the problems mentioned above and allow for fast and reliable yarn exchange as well as an apparatus which can rapidly and efficiently eliminate yarn looseness, and finally reached the present invention.